Multiple glazed units

ABSTRACT

This disclosure relates to multiple glazed units containing fluorocarbon gas and to the method and apparatus for producing such units.

United States Patent 1 1 1 3,735,553 Houser [4 1 May 29, 1973 [54] MULTIPLE GLAZED UNITS [561 References Cited [75] Inventor: Lloyd Houser, Lincoln, Ill. UNITED STATES PATENTS [73] Assignee: PPG Industries, Inc., Pittsburgh, Pa. 2,729,378 1/1956 Pujolyfont ..53/1 12 R X 2,756,467 7/1956 Etling ..52/304 X [22] Filed: Oct. 12, 1970 2,875,792 3/1959 Moyer ..52/304 X 3,078,627 2/l963 Dunipace et al ..53/22 X [21] App]. No.: 79,766

Primary Examiner-Travis S. McGehee 52 US. Cl ..53/86, 52/304, 53/112 R Attorneychlsholm & Spencer [51] Int. Cl. ..B65b 31/02 [58] Field of Search ..53/7, 22 R, 86, 112 R; [57] ABSTRACT 52/171 304 This disclosure relates to multiple glazed units containing fl uorocarbon gas and to the method and apparatus for producing such units.

3 Claims, 3 Drawing Figures PATENHDMYZQIBB 3,735,553

SHEET 2 BF 2 INVENTOR iLOYD HOUSE/ BY @khwgke ATTORNEYS MULTIPLE GLAZED UNIT S BACKGROUND OF THE INVENTION This invention relates to the manufacture of multiple glazed, insulating units. More particularly the present invention relates to purging all-glass multiple glazed units, filling the units with fluorocarbon gas and, there after, sealing the gas within the units to improve their insulation effectiveness, thus reducing heat loss due to indoor and outdoor temperature differentials.

The term fluorocarbon, as used herein, is intended to include all normally gaseous fluorine containing hydrocarbons having one to four carbon atoms, including compounds which may contain other halogen and/or hydrogen atoms in addition to the fluorine present. Included among the fluorocarbon compounds that are contemplated are: tetrafluoromethane, trifluoromethane, chlorotrifluoromethane, hexafluoroethane, bromotrifluoromethane, chlorodifluoromethanechloropentafluoroethane, chlorodifluoro-methane, chloropentafluoroethane, dichlorodifluoromethane,

l,l-difluoroethane, vinyl fluoride, vinylidene fluoride and mixtures thereof. These compounds are sold as Freon fluorocarbons by E. I. DulPont DeNemours & Company.

One commercially used process for making all-glass multiple glazed units is broadly disclosed in U. S. Pat. No. 2,624,979. This process proceeds by supporting two superposed sheets of glass, with the upper sheet slightly larger than the lower sheet, in slightly spaced relationship to each other, heating the margins of the upper sheet until they droop and become welded or fused with the margins of the lower sheet, pulling the upper sheet upwardly to provide a chamber between the sheets, and abruptly increasing the air pressure within the unit to effect filleting of the welded connection between the sheets. Each unit has at least one pore opening, either in a face or an edge thereof, through which air under pressure is introduced between the sheets to effect filleting and, also, which thereafter allows for equalization of the pressure of the air within the unit with atmospheric pressure during annealing and cooling of the unit. Subsequent to cooling the unit, additional treatment thereof includes purging and filling the unit with dry air and hermetically sealing the unit.

Recently it has been found to be desirable to fill or substantially fill all-glass multiple glazed units with low conductive, fluorocarbon gas or gases in order to increase their insulation effectiveness. However, because of the highly toxic nature of concentrated amounts of fluorocarbon gas and/or other deleterious efiects, e.g., corrosion of electrical contacts, etc., a need was created to devise a safe and efficient technique for filling all-glass multiple glazed units with such gases. Moreover, it was desirable that the technique to be used have a capability for permitting hermetic sealing of the units under conditions such that the gas within the unit is at a selected temperature and/or pressure relative to the atmospheric temperature and pressure at the location where the units are hermetically sealed. The present invention is directed toward providing such units and suitable procedures and apparatus for their manufacture.

ln accordance with the present invention, all-glass multiple glazed units are filled with low-conductive fluorocarbon gas in an environmental control chamber suitably fitted with apparatus permitting safe and efficient filling of the units and subsequent hermetic sealing of the units at a predetermined desired temperature and/or pressure.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the description that follows when taken in conjunction with the drawings, in which:

FIG. 1 is a perspective of a plurality of all-glass multiple glazed units during their manufacture in accordance with this invention;

FIG. 2 is a fragmentary view, partly in section, of a multiple glazed unit fitted with a purging or scavenging and filling device pursuant to this invention; and

FIG. 3 is a diagrammatic view of preferred apparatus for use in the practice of the invention.

Depicted in FIG. l are a plurality of all-glass multiple glazed units 10 comprised of a pair of glass sheets 12 and 14 that are welded together about their marginal edges. As best illustrated in FIG. 2, one of the glass sheets, 12, of each unit 10 provided with a pore hole or purge hole 16 defined by a cylindrical opening in metal eyelet 18 that extends through a marginal edge portion thereof. Pore hole 16 is in communication with the interior of the unit.

As shown in FIG. 1, units 10 are each supported on edge in a vertical position so that the pore hole 16 is preferably located in the upper disposed region of each unit. Also shown is a feed conduit or header 20 for conducting gases into the interior of the units and an exhaust conduit 22 for conducting gases from the interior space or chamber 24 defined by the fused glass sheets 12 and 14.

With particular reference to FIGS. l and 2, there is shown a purging or scavenging and filling device 26 comprised of a cylindrical housing 28 bored from one end to receive a small diameter fill or feed tube 30 and counterbored from the opposite end to provide a cylindrical space 32 around the fill tube 30, which space communicates with exhaust tube 34 connected thereto in a conventional manner. The counterbored end of housing 2%, as shown, has afiixed thereto a circular, resilient gasket 36 which is comprised of a material such as silicon rubber and has a central aperture 38 aligned with cylindrical space 32.

Scavenging and filling device 26 is constructed and arranged to be mounted on multiple glazed unit 10 so that fill tube 30 extends through space 32 and aperture 38 and projects into chamber 24 through pore hole 16. Exhaust gas to be removed from chamber 24 may pass around fill tube 30 and through aperture 38 into space 32 which communicates with exhaust tube 34. Supporting scavenging and filling device 26 in sealing engagement with glass sheet 12 and around pore hole 16, i.e., such that gasket 36 is under slight compression, is a wire spring and roller assembly 40 that embraces housing 28 and a marginal edge portion of glass sheet 14. Spring 42 is essentially comprised of a pair of parallel, C-shaped spring parts 44 joined at one common end by means of a connecting leg 46 extending perpendicularly thereto and pivotally mounted to housing 28 by means of leg 46 residing in slot 47. Roller 48 is mounted on a pair of opposed legs 50 that extend perpendicularly from the other end of each C-shaped spring part 44 and is preferably covered with a material such as silicon rubber to prevent scratching or marring of the portions of glass sheet 14 which it contacts.

With reference to FIG. 3, a typical purging or scavenging and filling operation of this invention will now be explained in detail. All-glass multiple glazed units, made as described above with reference to U. S. Pat. No. 2,624,979, are mounted on a rack 52 in a chamber 54. A purging or scavenging and filling device 26, as described in connection with FIGS. 1 and 2, is fitted about the pore hole of each unit. Exhaust fan 56 (located or ducted to the outside of the fabricating plant) is turned on and main exhaust valve 58 is opened, Then, purge valve 60 is opened permitting dry air from a source (not shown) to flow through feed conduit 20 and fill or feed tube 30 into space 24 of units 10. Valve 62 in conduit 72 is then opened permitting air under pressure to enter chamber 54 and door 64 is closed. Dry air is permitted to flow into space 24 of units while moist air is removed therefrom by means of exhaust tubes 34 and exhaust conduit 22 until the air within the units reaches a desired low-temperature dew point. At that point dry air valve 60 is closed and valve 66 is opened, permitting dry fluorocarbon gas, preferably chlorodifluoromethane gas, from a source (not shown) to flow through feed conduit 20 and fill or feed tube 30 into space 24 of units 10. Dry fluorocarbon gas is permitted to flow into space 24 of units 10 while the dry purge air is removed therefrom by means of exhaust tubes 34 and exhaust conduit 22 until the units are filled or substantially filled with fluorocarbon gas. Thereafter, the fluorocarbon gas valve is closed and exhaust flush valve 68 is opened flushing residual fluorocarbon gas from exhaust conduit 22.

Next, door 70 and main exhaust valve 58 are closed such that chamber 54 can now be pressurized by the flow of pressurized air entering the chamber through conduit 72. At a predetermined elevated pressure in chamber 54, as determined in accordance with U. S. Pat. No. 2,736,075, exhaust flush valve 68 is closed and either sequentially or by groups the scavenging or purging and filling devices 26 are removed from units 10 and the units are hermetically sealed, as by soldering closed the pore opening 16 in each metal eyelet 18. Valve 74, located outside of chamber 54, is constructed and arranged to permit a continuous flow of dilution air through the chamber during pressurization of the chamber. Valve 76, also located outside of chamber 54, is constructed and arranged to permit periodic opening and closing or cycling of this valve in response to and to compensate for the pressure in chamber 54 being on either side of the pressure or set point at which sealing of the units is to take place. After sealing of the units is completed, the pressure in chamber 54 is gradually reduced to ambient atmospheric outside the chamber, the doors are opened and the units are removed for final inspection and packing.

Although the present invention has been described with particular reference to specific details of certain embodiments thereof, it is not intended that such details shall be regarded as limitations upon the scope of the invention, except insofar as included in the accompanying claims. For example, it will be evident that the temperature of the fluorocarbon gas or of the chamber pressurization air or both may be adjusted, in addition to or in lieu of their pressure control, such that the fluorocarbon gas is sealed in the unit at a selected temperature and/or pressure relative to the atmospheric temperature and pressure outside the sealing chamber, i.e., normal atmospheric temperature and pressure at the time of sealing.

I claim:

1. Apparatus for improving the insulation effectiveness of a multiple glazed unit having a pair of opposed spaced glass sheets joined together around their marginal edges, at least one of said sheets being flat and provided with a single opening located adjacent a marginal edge portion of the unit comprising:

a. a housing having top and side walls and an open bottom, said housing being adapted to be positioned in spaced relation with respect to said flat glass sheet with the open bottom of the housing aligned with said opening in said flat glass sheet,

b. sealing means disposed between said housing and the surface of said adjacent flat glass sheet so as hermetically to seal the interior of the housing,

c. means for securing said housing and said sealing means to said multiple glazed unit,

d. gas conduit means extending into said housing, said conduit means being adapted to be selectively connected to sources of a dry purging gas and a gas of low thermal conductivity so as to introduce, sequentially, dry purging gas and a low thermal conductivity gas to the interior of said multiple glazed unit, and

e. an exhaust means connected to said housing for removing therefrom dry purging gas forced into said housing by the flow of the low thermal conductivity gas subsequently introduced into the interior of said glazed unit.

2. An apparatus according to claim 1 in which the gas conduit means extends through the opening of the housing and the opening in the flat glass sheet to a point adjacent said opposed spaced glass sheet.

3. An apparatus according to claim 1 in which said low thermal conductivity gas is more dense than the dry purging 

2. An apparatus according to claim 1 in which the gas conduit means extends through the opening of the housing and the opening in the flat glass sheet to a point adjacent said opposed spaced glass sheet.
 3. An apparatus according to claim 1 in which said low thermal conductivity gas is more dense than the dry purging gas. 